(a) Technical Field
The present disclosure relates generally to an apparatus and method for detecting a defect of a press panel. More particularly, the present disclosure relates to an apparatus and method for detecting a defect of a press panel, for determining whether a corresponding panel is defective using an elastic wave signal emitted during press work for manufacturing the panel.
(b) Description of the Related Art
In order to estimate soundness of materials or products, non-destructive inspection that does not affect a material or shape and dimension is often used. Examples of non-destructive inspection include macroscopic inspection, ultrasonic wave inspection, radiation inspection, and acoustic inspection. Among the examples listed above, macroscopic inspection is a method for checking whether there is an abnormality, e.g., whether there is a defect or whether a member is deformed by unassisted visual inspection, and for determining whether there is a defect by absorbing an inspection target by an inspector using equipment such as a magnifying glass. The macroscopic inspection does not require many inspection devices, and thus, the method may be simply performed; however, the method requires an inspector with sufficient knowledge and ability to perform the inspection. Whether a press panel is defective can be determined using the macroscopic inspection, and whether a detection target is defective is inspected by alternately monitoring two mirrors, which reflect upper and lower surfaces of the detection target that passes at a predetermined speed, by an inspector who stands in front of the two mirrors.
In addition, ultrasonic wave inspection inspects whether an internal part of a detection target is defective using properties whereby an ultrasonic wave beam applied to the detection target is reflected where an internal defect occurs. Information about whether there is a defect and a location of the defect may be acquired using intensity of the reflected ultrasonic wave energy and reflection time.
Meanwhile, radiation inspection for inspecting an internal defect of a product using X-rays or radioisotope is often used to detect a defect of a weld zone or a casting or a defect according to a change in radiation intensity on a radiography image acquired by irradiating a detection target with radiation. Although radiation inspection is a non-destructive inspection technique that is most frequently used in South Korea, the amount of transmitted radiation during an inspection for defect detection is 5 mSv that corresponds to 50 times higher than radiation used for an X-ray examination in hospitals. Accordingly, an inspector is at a risk for being exposed to radiation during the inspection and thus needs to pay particular attention.
Lastly, acoustic inspection inspects a defect using an elastic wave signal that is generated while a solid material is deformed or destroyed. In acoustic inspection, whether a defect is inspected while applying elastic stress to a detection target. A plurality of acoustic emission sensors may be installed in the detection target, a crack initiation site may be estimated via collected signals, and various information items such as the shape or degree of crack may be interpreted. In particular, acoustic inspection may enable wide area inspection compared with other non-destructive inspection and may also enable inspection while equipment or a structure is used. In addition, the acoustic inspection may enable real-time measurement and detect a defect location. However, signals collected through the acoustic emission sensor need to be interpreted dependent upon the inspector's experience, and background noise processing highly affects the accuracy of inspection.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore, it may contain information that does not form the related art that is already known in this country to a person of ordinary skill in the art.